Does MCV (Mean Corpuscular Volume) Fluctuate

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Yes, MCV, or mean corpuscular volume, can change for several reasons. MCV measures the average size of red blood cells, helping doctors diagnose and monitor anemia and other blood conditions. Here are some factors that can cause MCV to fluctuate:

Diet and Nutrition

What you eat affects your MCV. For instance, if you lack vitamins like B12 and folate, your MCV might go up, making your red blood cells larger (microcytosis). On the other hand, if you don’t get enough iron, your MCV could drop, making the cells smaller (microcytosis).

Hydration Levels:

How much water you drink impacts your MCV. Dehydration can make MCV appear higher because there’s less plasma in your blood, concentrating the red blood cells. Drinking too much water can have the opposite effect, diluting the blood and lowering MCV.

Alcohol Use

Drinking alcohol regularly can increase your MCV. Alcohol can damage the bone marrow where red blood cells are made, leading to larger cells.


Some medicines can change your MCV. Drugs like antiretroviral for HIV and chemotherapy for cancer can affect the size of your red blood cells, making MCV go up or down.

Health Conditions

Various health problems can alter MCV levels. For example, liver disease can cause an increase in MCV, while issues with the bone marrow might cause changes in either direction. Thyroid problems can also affect your red blood cells' size.


When you’re sick, your MCV might change temporarily. Your body’s response to stress or infection can cause these fluctuations.

Lab Differences

MCV readings can also vary because of differences in lab techniques, equipment, and the timing of your blood test. Small variations might just be due to how the test was done.

Because of these many factors, doctors look at the overall trend in your MCV levels rather than a single reading. This helps them understand your health better and make more accurate diagnoses.

To put it simply, MCV is an important measure but can change for many reasons. It helps to look at your diet, hydration, alcohol use, medications, health conditions, recent illnesses, and even how the test was conducted to understand why your MCV might be fluctuating. Monitoring MCV over time gives a clearer picture of your health.

Frequently Asked Questions

Q:1.  What is a normal MCV range? 

A: The normal MCV range for adults is usually between 80 to 100 femtoliters. However, this can slightly vary depending on the lab.

Q:2.  Can dehydration really affect my MCV? 

A: Yes, dehydration can make your MCV seem higher because there’s less liquid in your blood, which concentrates the red blood cells.

Q:3.  How does alcohol affect my MCV? 

A: Drinking a lot of alcohol can damage your bone marrow, making your red blood cells larger and increasing your MCV.

Q:4.  Should I be worried if my MCV is high? 

A: A high MCV can mean various things, like vitamin B12 or folate deficiency, liver disease, or alcohol use. It’s best to talk to your doctor to find out the exact cause.

Q:5.  Can my medications change my MCV? 

A: Yes, certain medications, such as those for HIV and chemotherapy, can increase your MCV because they affect how red blood cells are made.